FALMOUTH, Maine — Earlier this month, when Falmouth High School junior Sarah Caldwell was told to report to the principal’s office, two possibilities ran through her mind.

“This is either really good or really bad,” she recalled.

The news was good.

Caldwell learned on Feb. 10 that she is one of two Maine students chosen for the 2014 Prudential Spirit of Community Awards. In May, Caldwell will join 50 other U.S. high school students and 51 middle-schoolers in Washington, D.C., for a four-day event, which includes sightseeing, a visit to Capitol Hill and a dinner cruise on the Potomac River.

Story continues below advertisement.

Caldwell will also receive a $1,000 award and a silver medallion during ceremonies at the Smithsonian’s National Museum of Natural History and the U.S. Chamber of Commerce.

The awards recognize children for their volunteer community service, something to which the 16-year-old Caldwell has grown accustomed. Last September, Caldwell helped raise $23,000 for the New England Walk to Defeat ALS, a 5K event held at Portland’s Payson Park.

The cause was personal for the avid gymnast. The walk was toward the tail end of her father’s struggle with the fatal disease.

Less than a month later, on Oct. 2, Caldwell was called out of class for bad news. Her father, 56-year-old Jim Caldwell, had died.

ALS — amyotrophic lateral sclerosis or Lou Gehrig’s disease — is a “progressive neurodegenerative disease that affects nerve cells in the brain and the spinal cord,” according to the ALS Association. There is no cure.

Sarah Caldwell had become aware of her father’s condition a little more than a year earlier, when she discovered a bottle of medication belonging to her father, which piqued her curiosity. Through an Internet search, Caldwell learned the drug was a treatment for ALS. She also learned that patients with ALS have a life expectancy of three to five years.

“I kept that secret to myself for two months,” she recalled. “Those were two of the worst months of my life.”

Eventually, Caldwell’s parents disclosed the news.

For the next year, her father’s health deteriorated, but he maintained a positive spirit, despite his difficulty breathing.

In the summer of 2013, Caldwell contacted students and friends to let them know about her father’s disease and the ALS walk. More than 200 people joined her cause, she said.

Since then, Caldwell has raised an additional $600, which will be used to establish a foundation in her father’s name for ALS research.

After her father’s death, the Falmouth School Department’s service learning coordinator, Holly MacEwan, encouraged Caldwell to apply for the award program.

“I’m not much of an award person,” Caldwell said. “If you’re doing a community service, it should be a selfless act. But I decided that if I did do this, it would draw so much attention to the ALS Association and my cause.”

As it happens, the 2014 Prudential Spirit of Community Awards will end just as the National ALS Advocacy Day and Public Policy Conference begins in Washington, which Caldwell will also attend.